Light emitting and image sensing device and apparatus

ABSTRACT

There is provided a light emitting and image sensing device for a scene. The device is formed in a semiconductor substrate and comprises a photosensor component for sensing an image of the scene. The photosensor component is responsive to incident light from the scene and provides an electrical signal representative of the image. There is also a photoemitter component for emitting a light signal representative of the electrical signal, and a coupling component connecting the photosensor component with the photoemitter component.

RELATED APPLICATION

This application is a continuation application of U.S. patentapplication Ser. No. 11/775,224, file Jul. 9, 2007, which in turn was acontinuation-in-part application of U.S. patent application Ser. No.10/917,377, filed Aug. 13, 2004 and having first named inventor PaulSteven Schranz, and claims the priority benefit thereof.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a novel image sensor device, hereinreferred to as a light emitting and image sensing device, and theapparatus in which it is used.

2. Description of the Related Art

An embodiment of a conventional image sensor, in this case a CMOS imagesensor, is schematically illustrated in cross-section in FIG. 1. Amicrolens 30 focuses incident light, or photons 32, on a plurality ofphotodiodes 34 in a silicon substrate 36. Color filters 38 filterphotons of specific wavelengths so that each of the photodiodes 34collects photons within one of three ranges of wavelengths,corresponding to red, green and blue light.

An embodiment of a conventional active pixel element in a CMOS imagesensor is illustrated in schematic view in FIG. 2. The active pixelelement comprises a photodiode and an active pixel circuit indicatedgenerally by reference numerals 34.2 and 40 respectively. The photodiode34.2 provides a photosensor signal on conductor 42. The photosensorsignal on conductor 42 is read out through a buffer transistor 44 onto acolumn bus 46 when a row select transistor 48 is activated. A resettransistor 50 operates to reset the photodiode 34.2 to a known state.

A schematic plan view of the conventional image sensor is illustrated inFIG. 3. The conventional image sensor comprises a matrix of rows andcolumns of pixel elements indicated generally by reference numeral 52.Each of the pixel elements contains a photosensing structure andcorresponding support circuitry, such as the photodiode 34.2 and activepixel circuit 40, respectively, illustrated in FIG. 2.

There are many image sensor applications wherein a light source isrequired to illuminate a scene, or an object, so that the image sensorcan capture one or more images. Examples of such applications includebut are not limited to video surveillance, cell phones, digital camerasand digital video systems. During low ambient light level conditions thelight source is necessary for an image to be captured at all.

An example of a conventional infrared video surveillance camera is givenby U.S. Pat. No. 6,642,955 by Brent Midgley et al. Midgley describes aCCD type image sensor in a camera system that switches electronicallybetween infrared radiation sensing and visible light sensing dependingon ambient conditions. Furthermore, the camera in Midgley makes use ofeither incandescent or LED type illuminators. These illuminators arelocated external to the camera system, but may be in a camera systemenclosure along with the CCD image sensor.

An example of a CMOS sensor used in cell phone is given by U.S. Pat. No.6,730,900 by Hsish et al. in which is described a novel CMOS basedactive sensor array that, along with focusing optics, is preferablyincorporated into a cellular phone camera for producing electronicimages.

A disadvantage of the prior art is the lack of integration of a lightsource for image illumination with the image sensor. This has resultedin excessively large image sensor products for the applications listedabove. In the case of the video surveillance camera, the illuminator iseither in a separate enclosure altogether, or is mounted inside thecamera system enclosure thereby increasing the size.

Another disadvantage of the lack of integration is the inability to takeadvantage of an illumination apparatus. In a cell phone, for example,where space is a constrained, it is often not feasible to include theillumination apparatus. In this situation, a cell phone camera can onlybe used in conditions where ambient light is sufficient for itsoperation.

Furthermore, another disadvantage of the prior art is that by lack ofintegration the power consumption of the above mentioned products andapplications is excessively large.

BRIEF SUMMARY OF INVENTION

In one aspect of the present invention there is provided a lightemitting and image sensing device for a scene. The device is formed in asemiconductor substrate and comprises a photosensor component forsensing an image of the scene. The photosensor component is responsiveto incident light from the scene and provides an electrical signalrepresentative of the image. There is also a photoemitter component foremitting a light signal representative of the electrical signal, and acoupling component connecting the photosensor component with thephotoemitter component.

In another aspect of the present invention there is provided a lightemitting and image sensing device for a scene. The light emitting andimage sensing device is formed in a semiconductor substrate andcomprises a photoemitter means for illuminating the scene with light,and a photosensor means for sensing an image of the scene. Thephotosensor means is responsive to incident light from the scene.

In another aspect of the invention there is provided a light emittingand image sensing device that includes a photosensor means. Thephotosensor means comprises a matrix of rows and columns of photosensorstructures responsive to incident light upon the light emitting andimage sensing device. For each row in the matrix there is row selectcircuitry connected to each of the photosensor structures in the row forselectively designating for outputting output signals representative ofthe light sensed by the photosensor structure. For each column in thematrix there is column select circuitry connected to each of thephotosensor structures in the column for selectively designating foroutputting output signals representative of the light sensed by thephotosensor structures.

In another aspect of the invention there is provided a light emittingand image sensing device having a photoemitter means. The photoemittermeans includes an array of photoemitter structures operable to emitlight from the device and a photoemitter control means for controllingan emission of the light from the array of photoemitter structures.

In another aspect of the invention there is provided a light emittingand image sensing device having a photosensor means. The photosensormeans comprises a plurality of select lines, a plurality of signallines, and a plurality of pixel elements. The pixel elements include aphotosensor structure, and a switching means coupled between thephotosensor structure and one of the plurality of signal lines. Theswitching means is responsive to select signals on one or more of theplurality of select lines for conveying a photosensor signal between thephotosensor structure and the one of the plurality of signal lines.

In another aspect of the present invention there is provided a lightemitting and image sensing device for a scene. The light emitting andimage sensing device includes a photosensor means for sensing an imageof the scene and a photoemitter means for illuminating the scene withlight. The photosensor means is formed in a first semiconductorsubstrate and is responsive to incident light from the scene. Thephotoemitter means is formed in a second semiconductor substrate. Thesecond semiconductor substrate is attached to the first semiconductorsubstrate.

In another aspect of the present invention there is provided a lightemitting and image sensing device for a scene. The light emitting andimage sensing device includes a photosensor means for sensing an imageof the scene and a photoemitter means for illuminating the scene withlight. The photosensor means is formed in a first semiconductorsubstrate and is responsive to incident light from the scene. Thephotoemitter means is formed in a second semiconductor substrate. Thesecond semiconductor substrate is attached to the first semiconductorsubstrate. The light emitting and image sensing device further includesa photoemitter control circuit operable to control an emission of thelight from the photoemitter means. The photoemitter control circuit isformed in the first semiconductor substrate.

In another aspect of the present invention there is provided a lightemitting and image sensing device for a scene. The light emitting andimage sensing device includes a photosensor means for sensing an imageof the scene and a photoemitter means for illuminating the scene withlight. The photosensor means is formed in a first semiconductorsubstrate and is responsive to incident light from the scene. Thephotoemitter means is formed in a second semiconductor substrate. Thesecond semiconductor substrate is attached to the first semiconductorsubstrate. The photosensor means includes a matrix of rows and columnsof photosensor structures responsive to incident light upon the device.For each row in the matrix there is row select circuitry connected toeach of the photosensor structures in the row for selectivelydesignating for outputting output signals representative of the lightsensed by said photosensor structure. For each column in the matrixthere is column select circuitry connected to each of the photosensorstructures in said column for selectively designating for outputtingoutput signals representative of the light sensed by said photosensorstructures.

In another aspect of the invention there is provided a light emittingand image sensing device that is formed in a semiconductor substrate.The light emitting and image sensing device comprises a photoemitteroperable to emit electromagnetic radiation from the device, and aphotosensor responsive to electromagnetic radiation incident upon thedevice.

In another aspect of the invention there is provided a lens housing foran image sensor type camera, the camera for generating an image of ascene. The lens housing comprises a first light channel for guiding anemission of light from the image sensor to illuminate the scene, and asecond light channel for guiding light from the scene towards the imagesensor.

In another aspect of the invention there is provided a housing for alight emitting and image sensing device. The housing comprises a firstlight channel for emitted light from the light emitting and imagesensing device to illuminate a scene, and a second light channel forincident light from the scene towards the light emitting and imagesensing device.

In another aspect of the invention there is provided a housing for alight emitting and image sensing device. The housing comprises a firstlight channel for emitted light from the light emitting and imagesensing device to illuminate a scene, and a second light channel forincident light from the scene towards the light emitting and imagesensing device. The second light channel has an outer surface. The firstand second light channels have a common axis. The first light channelbeing formed around the outer surface of the second light channel.

In another aspect of the invention there is provided, in combination, alight emitting and image sensing device and a housing. The housing has afirst end where the light emitting and image sensing device is disposed.

In another aspect of the invention there is provided a method ofilluminating a scene and sensing an image. The method comprises thesteps of emitting light from a light emitting and image sensing device,channeling the emitted light along a first channel, dispersing the lightwith a first lens towards the scene, focusing incident light from thescene with a second lens, channeling the focused light along a secondchannel towards the light emitting and image sensing device, and sensingthe image of the scene with the focused light upon the light emittingand image sensing device.

BRIEF DESCRIPTION OF DRAWINGS

The invention will be more readily understood from the followingdescription of preferred embodiments thereof given, by way of exampleonly, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view in cross-section of a conventional CMOS imagesensor;

FIG. 2 is a schematic view of a conventional active pixel element;

FIG. 3 is a schematic plan view of a conventional image sensor;

FIGS. 4 a-h are schematic plan views of embodiments of light emittingand image sensing devices;

FIG. 5 is a schematic view in cross-section of an embodiment of thelight emitting and image sensing device in a silicon substrate;

FIG. 6 is a schematic view in cross-section of another embodiment of thelight emitting and image sensing device in a silicon substrate;

FIG. 7 is a broken-away schematic view in cross-section of an embodimentof the light emitting and image sensing device wherein a photoemitter isin a first semiconductor substrate and a pixel element is in a secondsemiconductor substrate;

FIG. 8 is a schematic view in cross-section of another embodiment of thelight emitting and image sensing device wherein a photoemitter is in afirst semiconductor substrate and a pixel element is in a secondsemiconductor substrate;

FIG. 9 is a partial schematic view of a matrix of active pixel elementsof the light emitting and image sensing device of FIG. 5;

FIG. 10 is a schematic view of an active pixel element of the lightemitting and image sensing device of FIG. 5;

FIG. 11 a-b are schematic views of embodiments of light emitting andimage sensing devices wherein an array of photoemitters is connected toa photoemitter control means;

FIG. 12 is a schematic view in perspective of the light emitting andimage sensing devices of the embodiments of FIGS. 4 a-c;

FIG. 13 is a schematic view in perspective of the light emitting andimage sensing devices of the embodiments of FIGS. 4 e-g;

FIG. 14 is a partial schematic view in perspective of the light emittingand image sensing device of the embodiment of FIG. 4 h;

FIG. 15 is a schematic view in perspective of an embodiment of a housingfor the light emitting and image sensing device of FIG. 4 h;

FIG. 16 is a cross-sectional schematic view of an embodiment of theinvention including the housing of FIG. 15 taken along line 16-16′, thelight emitting and image sensing device of FIG. 4 h, and a substrate;

FIG. 17 is a schematic view in perspective of an embodiment of a housinghaving adjacent light channels;

FIG. 18 is a cross-sectional schematic view of an embodiment of theinvention including the housing of FIG. 17 taken along line 18-18′,either one of the light emitting and image sensing devices of FIGS. 4e-g, and a substrate;

FIG. 19 is a schematic view in perspective of an embodiment of a housinghaving light channels with a common axis;

FIG. 20 is a cross-sectional schematic view of an embodiment of theinvention including the housing of FIG. 19 taken along line 20-20′,either one of the light emitting and image sensing devices of FIGS. 4a-d, and a substrate;

FIG. 21 is a broken-away schematic view in cross-section of a lightemitting and image sensing device wherein a photoemitter is in a firstsemiconductor substrate and a pixel element is in a second semiconductorsubstrate according to another embodiment of the present invention;

FIG. 22 is a side elevation view of a light emitting and image sensingapparatus according to another embodiment of the present invention;

FIG. 23 is a broken-away schematic view in cross-section of a lightemitting and image sensing device of the light emitting and imagesensing apparatus of FIG. 22; and

FIG. 24 is a broken-away schematic view in cross-section of the lightemitting and image sensing device of FIG. 23.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 4 a, a light emitting and image sensing device,indicated generally by reference numeral 60, is formed in asemiconductor and has a light emitting region 62 and an image sensingregion 64. The light emitting region 62 has a photoemitter 68. Thephotoemitter 68 operates to emit light, from a surface 66, to illuminatea scene, or an object. The emitted light is in a range of wavelengths,which can be in an infrared band, a visible light band or an ultravioletband of the electromagnetic spectrum. Other bands of the electricalmagnetic spectrum are, however, possible as well.

The image sensing region 64 has a plurality of pixel elements indicatedgenerally by reference numeral 70. The pixel elements 70 are responsiveto incident light from the scene, or the object. Each of the pixelelements 70 provides a photosensor signal representative of the incidentlight in the area of the respective pixel element. The plurality ofpixel elements 70 can be arranged in a matrix having rows and columns.An image sensor resolution is determined by a first number of pixelelements in each row and by a second number of pixel elements in eachcolumn.

Two further embodiments of the invention similar to the embodiment shownin FIG. 4 a are illustrated in FIGS. 4 b and 4 c wherein like parts havelike reference numerals with an additional suffix. The embodimentillustrated in FIG. 4 b includes a plurality of photoemitters 68.bpositioned in a photoemitter region 62.b around an image sensing region64.b. The embodiment illustrated in FIG. 4 c includes a plurality ofphotoemitters 68.c having a photoemitter density comparable to a pixelelement density.

Another embodiment of the invention is illustrated in FIG. 4 d whereinlike parts have like reference numerals with an additional suffix. Thelight emitting and image sensing device 60.d has a circular imagesensing region 64.d surrounded by a ring-shaped light emitting region62.d. The light emitting region 62.d has a plurality of photoemitters68.d. The image sensing region 64.d has a plurality of pixel elements70.d.

Three further embodiments of the invention are illustrated in FIGS. 4 e,4 f and 4 g wherein like parts have like reference numerals with anadditional suffix. The embodiment illustrated in FIG. 4 e includes alight emitting region 62.e adjacent an image sensing region 64.e. Thelight emitting region 62.e includes a photoemitter 68.e and the imagesensing region 64.e includes a plurality of pixel elements 70.e. Theplurality of pixel elements 70.e can be arranged in a matrix having rowsand columns. The embodiments illustrated in FIGS. 4 f and 4 g aresimilar to that of FIG. 4 e, both including a plurality of photoemitters68.f and 68.g respectively. The plurality of photoemitters 68.g has aphotoemitter density comparable to a pixel element density.

Another embodiment of the invention is illustrated in FIG. 4 h whereinlike parts have like reference numerals with an additional suffix. Inthis embodiment a plurality of photoemitters 68.h are arranged in analternating pattern with a plurality of pixel elements 70.h. Aphotoemitter density can be different than a pixel element density.

Another embodiment of the invention is illustrated in FIG. 5, whereinlike parts have like reference numerals with an additional suffix. Aphotoemitter indicated generally by reference numeral 68.5 is separatedfrom a pixel element indicated generally by reference numeral 70.5. Thephotoemitter 68.5 and the pixel element 70.5 are formed on and in afirst layer of silicon 74. The first layer of silicon is formed on topof a silicon oxide (SiO₂) layer 76, which is formed on top of a siliconsubstrate 78.

In this embodiment the photoemitter 68.5 is similar to a semiconductordevice for electro-optic applications described in European PatentEP1210752 by Coffa et al., which is incorporated by reference herein. AnN⁻ region 80, an N region 82 and a P⁺ region 84 are formed in thesilicon layer 74, and together make a PN junction that under reversebias emits light 92. One skilled in the art will recognize that the PNjunction is similar to a base-collector junction of a bipolar transistorhaving a base electrode 83, a collector electrode 85 and an emitterelectrode 87. A rare earth ions doped region 86, in this case Erbium,enables the PN junction to emit light 92 having a wavelength around 1.54um. Using other rare earth ions allows light to be emitted havingdifferent wavelengths. For instance, as a non-limiting example, Terbiumand Ytterbium provide light having a wavelength around 540 nm and 980 nmrespectively.

A trench, indicated generally by reference numeral 88, serves to reducelateral light transmission from the rare earth ions doped region 86towards the pixel element 70.5. The trench 88 has a wall 90 upon whichthere is a film of silicon oxide (SiO₂) 91. Light 92 travelling from therare earth ions doped region 86 towards the pixel element 70.5 throughthe semiconductor layer 74 must cross the wall 90 and travel through thefilm of silicon oxide (SiO₂) 91. The refractive index of silicon oxide(SiO₂) is less than the refractive index of silicon. This causes lightincident on the wall 90 having an angle of incidence, from a normal tothe wall, greater than a critical angle to undergo total internalreflection. In other embodiments multiple trenches having films ofsilicon oxide (SiO₂) can be used to further reduce lateral lighttransmission. The trench 88 has the advantage of reducing phantom imagesin and preventing blurring of pixel element 70.5 as caused by the abovementioned lateral light transmission.

The light 92 emitted from the rare earth ions doped region 86 has randomdirections. The light 92 strikes a surface 104, defined by a boundarybetween the silicon layer 74 and a silicon oxide layer 106, at variousangles of incidence to a normal to the surface. Light 92 having theangle of incidence greater then the critical angle will be internallyreflected. It is advantageous, then, that the light 92 be substantiallynormal to the surface 104 in order for maximum light emission from thesurface. The goal is to maximize an external quantum efficiency, aproblem well known in the art. In another embodiment, a photoemitter canbe provided similar to a device presented in “Si-based Resonant CavityLight Emitting Devices” by Castagna et al in SPIE Vol 5366, which isincorporated by reference herein. This has the advantage that lightgenerated is substantially normal to surface 104. This has a furtheradvantage of reducing lateral light transmission through thesemiconductor layer 74 towards the pixel element 70.5.

The pixel element 70.5 of the present embodiment is commonly known inthe prior art, as disclosed by U.S. Pat. No. 5,965,875 by Merril, whichis incorporated by reference herein, and as such will not be describedin great detail here. The pixel element 70.5 includes a photosensorstructure 72. The photosensor structure 72 is based on a triple wellstructure forming a first PN junction 94, a second PN junction 96 and athird PN junction 98. Incident light 100 having different wavelengthspenetrates the photosensor structure 72 at varying depths depending onthe wavelength. Red light penetrates to around the depth of the first PNjunction 94 where it produces a red photo current. Green lightpenetrates to around the depth of the second PN junction 96 where itproduces a green photo current. Blue light penetrates to around thedepth of the third PN junction 96 where it produces a blue photocurrent. A photocurrent sensor indicated generally by reference numeral102 measures the red, green and blue photocurrents.

When the incident light 100 is in the near ultraviolet and near infraredbands of the electromagnetic spectrum, the photosensor structure 72 isstill capable of functioning well. A study performed by Alternate VisionCorporation indicates that the photosensor structure 72 performs wellunder such conditions. The results of the study were published in apaper titled “Infrared and ultraviolet imaging with a CMOS sensor havinglayered photodiodes” by Gilblom et al.

The pixel element 70.5 of this embodiment is advantageous since it takesless area of surface 104 to sense red, green and blue components oflight 100. This allows increased resolution for a given surface area.Nevertheless, other image sensor structures formed in silicon can beused for the present invention. This includes CMOS image sensorstructures, such as in FIG. 1, and CCD image sensor structures.

Referring now to FIG. 6, another embodiment of the invention isillustrated wherein like parts have like reference numerals with anadditional suffix. The photoemitter 68.6 is in this case formed using aPN junction diode, indicated generally by reference numeral 108, withun-annealed implant dislocations used to enhance light emission. Thestructure of the PN junction diode 108 is described in great detail inU.S. Pat. No. 6,710,376 by Worley, which is incorporated by referenceherein. The pixel element 70.6 is similar to the pixel element 70.5 inFIG. 5.

The PN junction 108 is comprised of an N+ implant region 110, in a dopedP type region 112, and a P+ implant 114 that is used to make a goodelectrical connection between the P-type region and metal terminals 116.A connection is made to the N+ implant region 110 using the metalterminal 118.

Several light emitting devices are known in the prior art that use III-Vor II-VI semiconductors and compound semiconductors, for example LEDs,resonant cavity light emitting diodes (RCLED) and vertical cavitysurface emitting lasers (VCSEL). It would be advantageous to includethese types of devices with a silicon based image sensor.

Another embodiment of the invention is illustrated in FIG. 7 whereinlike parts have like reference numerals with an additional suffix. Afirst semiconductor substrate 120 is illustrated above a secondsemiconductor substrate 122. The first semiconductor substrate 120 isformed from III-V or II-VI compound semiconductor materials, whereas thesecond semiconductor substrate 122 is formed from silicon. Aphotoemitter 68.7 is formed in the first semiconductor substrate 120,and a pixel element 70.7 is formed in the second semiconductor substrate122. The pixel element 70.7 is similar to the pixel element 70.5 in FIG.5.

In the present embodiment, the photoemitter 68.7 is similar to a lightemitting device disclosed in U.S. Pat. No. 5,493,577 by Choquette et al,which is incorporated by reference herein, wherein the light emittingdevice has a structure compatible for both RCLEDs and VCSELs. Thephotoemitter 68.7 comprises a first distributed Bragg reflector (DBR)124, a second DBR 126, an active region 128 and a control layer 130. Thefirst and second DBRs 124 and 126 and the active region 128 form aresonator, or what is commonly called a Fabry-Perot resonator. Asubstrate 132 attaches the first DBR 124 to a first electrode 134. Asecond electrode 136 is deposited on the second DBR 126. Choquettedescribes the operation of the photoemitter 68.7 for RCLED and VCSELembodiments in great detail.

Light 92.7 is emitted substantially along an axis and normal to asurface 140. Since the index of refraction of the second DBR 126 isgreater than that of air, the surrounding environment, this has theadvantage of minimizing the effects of internal reflection at thesurface 140. This increases an external quantum efficiency of thephotoemitter 68.7. Another advantage of the orientation of light 92.7 tosurface 140 is that light is substantially not emitted towards thephotosensor structure 72.7. This prevents the formation of phantomimages in and/or blurring of the pixel element 70.7. In this embodimentthe light 92.7 has a wavelength of 980 nm which is in the near infraredregion.

The first semiconductor substrate 120 is attached to the secondsemiconductor substrate 122. The first electrode 134 is operativelyconnected to photoemitter control circuitry 138, which can enable,disable and control the intensity of light emission of the photoemitter68.7. Attaching different types of semiconductor substrates together,for instance GaAs and Si, and providing many electrical connectionsbetween them is well known in the art. The company Xanoptix Inc.provides such hybrid integrated circuit technology.

In another embodiment, a light emitting and image sensing device using aIII-V compound semiconductor substrate and a silicon substrate isillustrated in FIG. 8, wherein like parts have like reference numeralswith an additional suffix. In this embodiment, the photoemitter 68.8,again, is formed in the first semiconductor substrate 120.8, and thepixel element 70.8 is formed in a second semiconductor substrate 122.8.The photoemitter 68.8 is similar in structure to a VCSEL disclosed inU.S. Pat. No. 6,590,917 by Nakayama et al., which is incorporated byreference herein. The photoemitter 68.8 includes an n-type GaAssubstrate 150, an epitaxial n-type GaAs layer 152, an n-type DBR 154, anactive layer region 156, a p-type DBR 158, a first mode control layer160, a second mode control layer 162 and an electrode 164.

The photoemitter 68.8 is similar in structure to a VCSEL disclosed inU.S. Pat. No. 6,590,917 by Nakayama et al. The photoemitter 68.8includes an n-type GaAs substrate 150, an epitaxial n-type GaAs layer152, an n-type DBR 154, an active layer region 156, a p-type DBR 158, afirst mode control layer 160, a second mode control layer 162 and anelectrode 164.

Light 92.8, again, is emitted substantially normal to a surface 140.8having the advantage of increasing an external quantum efficiency andminimizing light emitted towards the photosensor structure 72.8.

Referring back to FIGS. 4 a-h, the light emitting and image sensingdevices 60 and 60 b-h include the plurality of pixel elements 70 and 70b-h respectively. Each one of the pixel elements 70 and 70 b-h can bethe pixel element 70.5 illustrated FIG. 5. In another embodiment, thepixel element 70.5 illustrated in FIG. 5, and similarly the pixelelements 70.6, 70.7 and 70.8 illustrated in FIGS. 6, 7, and 8respectively, can be arranged in a matrix configuration as illustratedin FIG. 9, wherein like parts have like reference numerals with anadditional suffix. Four such pixel elements 70.9 are illustrated in FIG.9 in a matrix having two rows and two columns (2×2), however, there maybe any number of rows and columns. Each pixel element 70.9 comprises aphotosensor structure and an active pixel circuit indicated generally byreference numeral 72.9 and 170 respectively. The pixel element 70.9 isfurther illustrated in FIG. 10, wherein the active pixel circuit 170 ispresented in greater detail. The operation of the pixel elements 70.9 isdescribed in great detail in Merril.

Again, referring back to FIGS. 4 b-d and 4 f-h, the light emitting andimage sensing devices 60 b-d and 60 f-h include a plurality ofphotoemitters 68 b-d and 68 f-h respectively. In another embodiment, aplurality of photoemitters 68.11 in a light emitting and image sensingdevice is controlled by a photoemitter controller 138.11 as illustratedin FIGS. 11 a-b, wherein like parts have like reference numerals with anadditional suffix. The photoemitter controller 138.11 enables thephotoemitters 68.11 to emit light, disables the emission of light andcontrols the intensity of emitted light. The photoemitter controller138.11 can be an adjustable current source, for example, which is wellknown in the art. The light emitting and image sensing device includesthe photoemitter controller 138.11. In other embodiments, thephotoemitter control means 138.11 can be external of a light emittingand image sensing device. In this case, the photoemitters 68.11 areconnected to the photoemitter controller 138.11 by an electricalconnector for example a connecting pin, or pad.

Referring back to FIG. 5, and similarly with FIGS. 6, 7 and 8, thetrench 88 operates to reduce light transmission from the photoemitter68.5 towards the pixel element 70.5. In another embodiment of theinvention illustrated in FIG. 12, wherein like parts have like referencenumerals with an additional suffix, a trench 88.12 separates two regionsin a semiconductor layer 74.12, for instance a silicon layer. The trench88.12 extends from a surface 172 to a boundary surface 174 between thesemiconductor layer 74.12 and a layer 78.12, for instance a siliconoxide (SiO₂) layer. A light emitting region 62.12 and an image sensingregion 64.12 correspond to the corresponding regions in the lightemitting and image sensing devices 60, 60.b and 60.c of FIGS. 4 a-crespectively. The trench 88.12 serves to substantially reduce lighttransmission from the light emitting region 62.12 through thesemiconductor layer 74.12 towards the image sensing region 64.12. Whenthe semiconductor layer 74.12 is silicon (or doped silicon) the trench88.12 can have a wall, next to the light emitting region 62.12, whichhas a film of silicon oxide (SiO₂) thereon.

In another embodiment of the invention illustrated in FIG. 13, whereinlike parts have like reference numerals with an additional suffix, atrench 88.13 in a semiconductor substrate 74.13 separates a lightemitting region 62.13 and an image sensing region 64.13. The lightemitting region 62.13 and the image sensing region 64.13 correspond tothe corresponding regions in the light emitting and image sensingdevices 60 e-g of FIGS. 4 e-g respectively. Again, the trench 88.13serves to substantially reduce light transmission from the lightemitting region 62.13 through the semiconductor layer 74.13 towards theimage sensing region 64.13.

FIG. 14 illustrates another embodiment of the invention, wherein likeparts have like reference numerals with an additional suffix. Aplurality of trenches 88.14 in a semiconductor substrate 74.14 separatea plurality of light emitting regions 62.14 from an image sensing region64.14. The plurality of light emitting regions 62.14 containphotoemitters corresponding to the photoemitters 68.h of the lightemitting and image sensing device 60.h of FIG. 4 h. The image sensingregion 64.14 contains a plurality of pixel elements corresponding to thepixel elements 70.h of the light emitting and image sensing device 60 hof FIG. 4 h.

Another embodiment of the invention is illustrated in FIGS. 15 and 16,wherein like parts have like reference numerals with an additionalsuffix. Referring to FIG. 16 first, a light emitting and image sensingdevice 60.16 is mounted on a substrate 182, for instance a printedcircuit board (PCB), and a single light channel housing 180 is mountedto the substrate overtop the light emitting and image sensing device.The light emitting and image sensing device 60.16 in this embodiment canbe the device 60.h illustrated in FIG. 4 h.

Referring to FIGS. 15 and 16, the single channel housing 180 has a firstend 184 and a second end 186 and a light channel 185. A lens 188 isattached at the first end 184. The first and second ends 184 and 186 canhave different shapes, for instance circular, square or rectangular. Thelight channel 185 has an inner surface 187. The inner surface 187 can beshaped such that at the first end 184 it is one shape, for instanceannular, and at the second end 186 it is a second shape, for instancesquare, with a smooth transformation of the inner surface between theends 184 and 186.

Another embodiment of the invention is illustrated in FIGS. 17 and 18,wherein like parts have like reference numerals with an additionalsuffix. Referring to FIG. 18 first, a light emitting and image sensingdevice 60.18 is mounted on a substrate 182.18, and an adjacent lightchannel housing 180.18 is mounted to the substrate overtop the lightemitting and image sensing device. The light emitting and image sensingdevice 60.18 in this embodiment can be either one of the devices 60.e,60.f and 60.g illustrated in FIGS. 4 e, 4 f and 4 g respectively.

Referring to FIGS. 17 and 18, the adjacent light channel housing 180.18has a first light channel 190 adjacent a second light channel 192. Thefirst light channel 190 has opposite ends 194 and has a lens 198attached at one end thereof. The lens 198 can be biconcave as well asother types of diverging lenses. Light from a light emitting region62.18 of the light emitting and image sensing device 60.18 travelsthrough lens 198 towards a scene, or an object. The lens 200 can bebiconvex as well as other types of converging lenses. The opposite ends194 can have different shapes, for instance circular, rectangular orsquare. The second light channel has opposite ends 196 and has a lens200 attached at one end thereof. Light from the scene or the objecttravels through lens 200 towards an image sensing region 64.18 of thelight emitting and image sensing device 60.18. The opposite ends 196 canhave different shapes, for instance circular, rectangular or square.

Another embodiment of the invention is illustrated in FIGS. 19 and 20,wherein like parts have like reference numerals with an additionalsuffix. Referring to FIG. 20 first, a light emitting and image sensingdevice 60.20 is mounted on a substrate 182.20, and a dual light channelhousing 180.20 is mounted to the substrate overtop the light emittingand image sensing device. The light emitting and image sensing device60.20 in this embodiment can be either of the devices 60, 60.b and 60.cof FIGS. 4 a, 4 b and 4 c respectively.

Referring to FIGS. 19 and 20, the dual light channel housing 180.20 hasa first light channel 190.20, having an axis 191, and a second lightchannel 192.20 having the same axis 191. The first light channel hasopposite ends 194.20 and has a lens 198.20 attached at one end thereof.The lens 198.20 can be biconcave as well as other types of diverginglenses. Light from a light emitting region 62.20 of the light emittingand image sensing device 60.20 travels through the lens 198.20 andtowards a scene, or an object. The opposite ends 194.20 can havedifferent shapes, for instance circular, rectangular or square. Thesecond light channel has opposite ends 196.20 and has a lens 200.20attached at one end thereof. The lens 200.20 can be biconvex as well asother types of converging lenses. Light from the scene, or the object,travels through the lens 200.20 towards an image sensing region 64.20 ofthe light emitting and image sensing device 60.20. The opposite ends196.20 can have different shapes, for instance circular, rectangular orsquare. Typically, the shapes of the opposite ends 194.20 of the firstlight channel 190.20 correspond to the shapes of the opposite ends196.20 of the second light channel 192.20.

Another embodiment of the invention is illustrated in FIG. 21 whereinlike parts to previous embodiments have like reference numerals with anadditional suffix ‘21’. A first semiconductor substrate 120.21 isillustrated above a second semiconductor substrate 122.21. The firstsemiconductor substrate 120.21 can be formed from III-V or II-VIcompound semiconductor materials, or organic polymers, whereas thesecond semiconductor substrate 122.21 is formed from silicon. Aphotoemitter 68.21 is formed in the first semiconductor substrate120.21, and a pixel element 70.21 is formed in the second semiconductorsubstrate 122.21. The pixel element 70.21 is similar to the pixelelement 70.5 in FIG. 5. The photoemittier 68.21 can be in the form of aninfrared LED, an organic LED, or an RGB LED.

Another embodiment of the present invention is illustrated in FIGS. 22,23 and 24 wherein like parts to previous embodiments have like referencenumerals with an additional suffix ‘22’. There is a light emitting andimage sensing device 60.22 connected with a printed circuit board 212.The light emitting and image sensing device 60.22 has a plurality ofpixel elements 70.22 on one side of the device 60.22. The pixel elements70.22 transform image light into electrical signals. On the oppositeside of the device 60.22 is a photoemitter 210. The photoemitter 210 iselectrically coupled to the pixel elements 70.22, however other forms ofcoupling such as optical coupling can be used. The photoemitter 210sequentially emits light signals representative of respective ones ofthe electrical signals of the pixel elements 70.22. In otherembodiments, the electrical signals of the pixel elements 70.22 can beencoded into an encoded signal, which can be emitted in the form of anencoded light signal by the photoemitter 210. The photoemitter 210transfers the electrical image captured by the device 60.22 off thedevice into an optical coupler 216 through a channel 214 in the printedcircuit board 212. The optical coupler 216 is connected with a fiberoptic cable 218 which carries the light signals generated by thephotoemitter 210 to a remote destination.

Referring to FIG. 24, a more detailed description of the light emittingand image sensing device is now given. A first semiconductor substrate122.22 is illustrated above a second semiconductor substrate 120.22. Thefirst semiconductor substrate 122.22 is formed from silicon. The secondsemiconductor substrate 120.22 can be formed from III-V or II-VIcompound semiconductor materials, or organic polymers. A pixel element70.22 is formed in the first semiconductor substrate 122.22. The pixelelement 70.22 is similar to the pixel element 70.5 in FIG. 5, howeverother pixel element structures are possible. A photoemitter 210 isformed in the second semiconductor substrate 120.22. The photoemittier210 can be in the form of an infrared LED, an RCLED, or a VCSEL, asdescribed previously, but other forms are possible as well. The pixelelements 70.22 can be arranged in a matrix configuration as illustratedin FIG. 9 and described previously. Each of the pixel elements 70.22 issimilar to the pixel element illustrated in FIG. 10 and describedpreviously. Note that other pixel element configurations and structuresare possible, and this example is not intended to limit the invention.The photoemitter 210 can include a photoemitter controller, similar tothat illustrated in FIG. 11 a or 11 b, and described earlier, howeverother photoemitter controllers are possible. Note that in otherembodiments the photoemitter 210 can be formed in a silicon layer 78.22of the first semiconductor substrate 122.22, e.g. similar to thephotoemitter in FIGS. 5 and 6.

As will be apparent to those skilled in the art, modifications can bemade to the above-described invention within the scope of the appendedclaims.

1. A light emitting and image sensing device for a scene, the deviceformed in a semiconductor substrate, the device comprising: aphotosensor means for sensing an image of the scene, the photosensormeans being responsive to incident light from the scene and providing anelectrical signal representative of the image; a photoemitter means foremitting a light signal representative of the electrical signal; and acoupling means connecting the photosensor means with the photoemittermeans.
 2. The device as claimed in claim 1, wherein the semiconductorsubstrate is a silicon substrate, the photoemitter means and thephotosensor means being formed in the silicon substrate.
 3. The deviceas claimed in claim 1, wherein the device further includes aphotoemitter control circuit operable to control an emission of thelight from the photoemitter means, the control circuit being formed inthe semiconductor substrate.
 4. The device as claimed in claim 1,wherein an optical barrier substantially optically separates thephotoemitter means from the photosensor means, the optical barrier beingformed in the semiconductor substrate.
 5. The device as claimed in claim1, wherein the photoemitter means includes a light emitting diode. 6.The device as claimed in claim 2, wherein the photoemitter meansincludes a PN junction implanted with a rare earth ion.
 7. The device asclaimed in claim 1, wherein the photoemitter means includes a resonantcavity light emitting diode.
 8. The device as claimed in claim 1,wherein the photoemitter means includes a vertical cavity surfaceemitting laser.
 9. The device as claimed in claim 2, wherein thephotoemitter means includes a MOS capacitor having a gate dielectric,the MOS capacitor being formed on the silicon substrate, the gatedielectric being implanted with a rare earth ion.
 10. The device asclaimed in claim 1, wherein the photosensor means comprises: a matrix ofrows and columns of photosensor structures responsive to incident lightupon the device; for each row in said matrix, row select circuitryconnected to each of the photosensor structures in said row forselectively designating for outputting output signals representative ofthe light sensed by said photosensor structure; and for each column insaid matrix, column select circuitry connected to each of thephotosensor structures in said column for selectively designating foroutputting output signals representative of the light sensed by saidphotosensor structures.
 11. The device as claimed in claim 1, whereinthe photosensor means comprises: a plurality of select lines; aplurality of signal lines; and a plurality of pixel elements, a pixelelement including: a photosensor structure; and switching means coupledbetween the photosensor structure and one of the plurality of signallines, the switching means responsive to select signals on one or moreof the plurality of select lines for conveying a photosensor signalbetween the photosensor structure and the one of the plurality of signallines.
 12. A light emitting and image sensing device for a scenecomprising: a photosensor means for sensing an image of the scene, thephotosensor means being formed in a first semiconductor substrate andbeing responsive to incident light from the scene and providing anelectrical signal representative of the image; and a photoemitter meansfor emitting a light signal representative of the light signal, thephotoemitter means being formed in a second semiconductor substrate; thesecond semiconductor substrate being connected with the firstsemiconductor substrate.
 13. The device as claimed in claim 12, whereinthe first semiconductor substrate is a silicon substrate.
 14. The deviceas claimed in claim 12, wherein the device further includes aphotoemitter control circuit operable to control an emission of thelight from the photoemitter means, the control circuit being formed inthe first semiconductor substrate.
 15. The device as claimed in claim12, wherein the photoemitter means includes a light emitting diode. 16.The device as claimed in claim 12, wherein the photoemitter meansincludes a resonant cavity light emitting diode.
 17. The device asclaimed in claim 12, wherein the photoemitter means includes a verticalcavity surface emitting laser.
 18. The device as claimed in claim 12,wherein the photosensor means comprises: a matrix of rows and columns ofphotosensor structures responsive to incident light upon the device; foreach row in said matrix, row select circuitry connected to each of thephotosensor structures in said row for selectively designating foroutputting output signals representative of the light sensed by saidphotosensor structure; and for each column in said matrix, column selectcircuitry connected to each of the photosensor structures in said columnfor selectively designating for outputting output signals representativeof the light sensed by said photosensor structures.
 19. The device asclaimed in claim 12, wherein the photosensor means comprises: aplurality of select lines; a plurality of signal lines; and a pluralityof pixel elements, a pixel element including: a photosensor structure;and switching means coupled between the photosensor structure and one ofthe plurality of signal lines, the switching means responsive to selectsignals on one or more of the plurality of select lines for conveying aphotosensor signal between the photosensor structure and the one of theplurality of signal lines.